Promoted Electrocatalytic Nitrogen Fixation in Fe-Ni Layered Double Hydroxide Arrays Coupled to Carbon Nanofibers: The Role of Phosphorus Doping.

The key to bringing the electrocatalytic nitrogen fixation from conception to application lies in the development of high-efficiency, cost-effective electrocatalysts. Layered double hydroxides (LDHs), also known as hydrotalcites, are promising electrocatalysts for water splitting due to multiple metal centers and large surface areas. However, their activities in the electrocatalytic nitrogen fixation are unsatisfactory. Now, a simple and effective way of phosphorus doping is presented to regulate the charge distribution in LDHs, thus promoting the nitrogen adsorption and activation. The P-doped LDHs are further coupled to a self-supported, conductive matrix, that is, a carbon nanofibrous membrane, which prevents their aggregation as well as ensuring rapid charge transfer at the interface. By this strategy, decent ammonia yield (1.72×10-10  mol s-1  cm-2 ) and Faradaic efficiency (23 %) are delivered at -0.5 V vs. RHE in 0.1 m Na2 SO4 .